There have heretofore been known apparatus which generate singing voices by synthesizing voices of lyrics while varying a pitch in accordance with a melody. Patent Literature 1, for example, discloses a technique for updating or controlling a singing position in lyrics, indicated by lyrics data, in response to receipt of performance data (pitch data). Namely, Patent Literature 1 discloses a technique in which a melody performance is executed by a user operating an operation section, such as a keyboard, and the lyrics are caused to progress in synchronism with a progression of the melody performance. Further, in the field of electronic musical instruments, controllers of various shapes have been under development, and it has been known to provide a grip section projecting from the body of a keyboard musical instrument and provide, on the grip section, a desired operation section and an appropriate detection section for detecting a manual operation performed on the operation section (see, for example, Patent Literature 2 and Patent Literature 3).
Further, Patent Literature 4, for example, discloses a technique in which a plurality of lyrics are displayed on a display device, a desired portion of the lyrics is selected through an operation of an operation section, and the selected portion is output as a singing voice of a designated pitch. Patent Literature 4 also discloses a construction in which a user designates a syllable of the lyrics displayed on a touch panel, and then, once the user performs key depression successively three times on a keyboard, the designated syllable is audibly generated or sounded with a pitch designated on the keyboard.